checker: missing type checking when generic fn is passed to generic struct fn #26195
Description
Describe the bug
Code: https://play.vlang.io/p/ed9aede158
struct Foo[T] {
bar T
}
fn (f Foo[T]) bar[U](op fn (T) U) U {
return op(f)
}
fn main() {
f := Foo{'hello'}
println(f.bar(fn (s string) int {
return s.len
}))
}Reproduction Steps
See included code.
Expected Behavior
As the function param takes string, op() should not be callable with Foo[T]. This should be a checker error.
Additionally, I am missing the generic for T, it should probably be bar[T, U].
Current Behavior
Output:
/box/code.v:6: error: cannot convert 'struct main__Foo_T_string' to 'struct string'
builder error:
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .
Exited with error status 1
Possible Solution
No response
Additional Information/Context
No response
V version
V 0.4.12 12f04b5
Environment details (OS name and version, etc.)
|V full version |V 0.4.12 12f04b50a75652ec54ad6f7ead7bdc37eecb8202
|:-------------------|:-------------------
|OS |linux, Debian GNU/Linux 12 (bookworm) (VM)
|Processor |2 cpus, 64bit, little endian, Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz
|Memory |0.68GB/2.02GB
| |
|V executable |/home/admin/v/v
|V last modified time|2025-12-28 20:25:33
| |
|V home dir |OK, value: /home/admin/v
|VMODULES |OK, value: .vmodules
|VTMP |OK, value: /tmp/v_0
|Current working dir |OK, value: /home/admin/playground
| |
|Git version |git version 2.39.5
|V git status |N/A
|.git/config present |true
| |
|cc version |cc (Debian 12.2.0-14+deb12u1) 12.2.0
|gcc version |gcc (Debian 12.2.0-14+deb12u1) 12.2.0
|clang version |Debian clang version 14.0.6
|tcc version |tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
|tcc git status |Error: fatal: detected dubious ownership in repository at '/home/admin/v/thirdparty/tcc'
To add an exception for this directory, call:
git config --global --add safe.directory /home/admin/v/thirdparty/tcc
Error: fatal: detected dubious ownership in repository at '/home/admin/v/thirdparty/tcc'
To add an exception for this directory, call:
git config --global --add safe.directory /home/admin/v/thirdparty/tcc
|emcc version |N/A
|glibc version |ldd (Debian GLIBC 2.36-9+deb12u10) 2.36
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